The present invention relates to a disposable diaper.
A typical example of the open type disposable diaper having tape fastener means used to fasten front and rear bodies to each other at the level of the waist line is disclosed in Japanese Patent No. 1977-40267. This example comprises a liquid-permeable topsheet, a liquid-impermeable backsheet, and a liquid-absorbent panel sandwiched therebetween, wherein a pair of side flaps are formed by portions of the top- and backsheets extending outward beyond laterally opposite sides of the panel, and the respective side flaps are formed at a crotch level with cutouts destined to define leg-openings around which the respective side flaps are provided with elastic members serving to seal the side flaps around the respective legs of the wearer and wherein the rear body is provided at laterally opposite sides thereof with tape fasteners used to fasten the rear body to the front body.
As the diaper disclosed in the above-identified Japanese Patent No. 1977-40267 is typical, the cutouts formed in opposite sides of the crotch zone for improving the fitness of the diaper to the wearer""s body necessarily reduce the width of the crotch zone and it is practically impossible for the crotch zone to thoroughly surround the wearer""s thighs. The crotch zone thus width-reduced inevitably decreases the ability of the crotch zone to absorb liquid excretion, particularly when liquid excretion readily occurs along opposite side edges of the crotch zone.
Generally, in the well known diaper of the type as disclosed in the above-identified Japanese Patent, a fold line of the crotch zone corresponding to a boundary line of front and rear bodies horizontally extends parallel to the waist line. In addition, the liquid-absorbent panel has so-called semi-rigidity, since it often comprises a more or less compressed accumulation of fluff pulp and tissue papers covering top- and bottom surfaces of this accumulation. Accordingly, a crotch zone of the diaper can not fit the corresponding zone of the wearer""s body, thus not only giving the wearer a feeling of incompatibility but also causing leakage of excretion.
In view of the problem as mentioned above, it is a principal object of the invention to provide a disposable diaper having a crotch zone configured so as to combine the advantage of an open type diaper with the advantage of a short-pants type diaper that has thoroughly covering portions surrounding the legs of a wearer and thereby eliminates the drawbacks of the well known diaper as mentioned above.
The advantage of the open type diaper lies in that the diaper can be adjustably tightened around a waist-opening as well as around leg-openings and the advantage of the short-pants type diaper lies in that the diaper has hoses to cover at least inner sides of the wearer""s thighs and the crotch zone can be dimensioned to be larger than that in the well known diaper.
To achieve the object set forth above, the invention generally resides in a disposable diaper comprising front and rear bodies, characterized by that said front and rear bodies are separately formed and welded together adjacent lower ends along a welding line convexly curved toward the waist line of said front and rear bodies so as to define a crotch zone, wherein an auxiliary liquid-absorbent panel that is elongated longitudinally with respect to said front and rear bodies is bonded at least at longitudinally opposite ends thereof to the top surface of said crotch zone. The auxiliary liquid-absorbent panel, in a preferred embodiment, is positioned in the crotch zone and mounted so as to float at a spaced distance from the welding line of the convexly curved crotch zone.
Preferably, said crotch zone defined by said convexly curved welding line is formed along its outer edges with a correspondingly curved cutout.
With the article constructed according to the invention as outlined above, the auxiliary liquid-absorbent panel is reliably centered to the wearer""s crotch and laterally opposite sides of the crotch zone cover at least the inner sides of wearer""s thighs. In this manner the crotch zone of the diaper covers substantially the entire crotch of the wearer.